This invention relates to an improved process for hydrotreating hydrocarbon-containing feed streams, especially heavy oils. In another aspect, this invention relates to the use of a polymeric treating agent for upgrading heavy oils.
Many liquid hydrocarbon-containing streams such as heavy crude oils, heavy residua, products from extraction and/or liquefaction of coal and lignite, products from tar sands and shale oil contain sulfur, metals, coke precursors and materials boiling in excess of 1,000.degree. F. (at 1 atm). The presence of these impurities makes further processing of heavier fractions difficult since they generally cause the deactivation of catalysts employed in processes such as catalytic hydrogenation and hydrocracking. Heavy oils are also quite viscous due to the high content of high molecular weight carbonaceous materials called heavies, and it is thus difficult to transport these heavy oils through pipelines.
It is well known to hydrotreat (hydrofine) liquid hydrocarbon-containing feed streams such as heavy oils, which contain undesirable metal and sulfur compounds as impurities and also considerable amounts of cokable materials and heavies, so as to convert them to lower boiling materials having lower molecular weight and lower viscosity than the feed hydrocarbons and to remove at least a portion of metal and sulfur impurities. A specific type of hydrotreating process is heat-soaking, preferably with agitation, in the presence of hydrogen but preferably in the absence of a solid, inorganic catalyst, hereinafter referred to as hydrovisbreaking. There is an ever present need to improve such hydrovisbreaking processes utilizing more efficient and/or less expensive hydrotreating agents than those presently employed.